Intercalated Montmorillonite Reinforced Polyimide Separator Prepared by Solution Blow Spinning for Lithium-Ion Batteries

We aimed at a novel method for the fabrication of an intercalated organic montmorillonite (OMMT)-reinforced polyimide (PI) separator with large-scale production and low cost in this study. Specifically, thermal-resistant PI/OMMT hybrid separators with a porous three-dimensional network structure were fabricated via solution blow spinning (SBS) and subsequent thermal imidization. Beforehand, OMMT with an expanded interlayer spacing was obtained by intercalation modification with cetyltrimethyl ammonium bromide. The influence of incorporated OMMT on the morphology, porosity, electrolyte uptake, and mechanical and electrochemical properties of PI/OMMT hybrid separators was evaluated. Unexpectedly, tensile tests proved that the incorporation of OMMT significantly enhanced the mechanical strength of the hybrid separator by 102.6% in comparison with that of the pristine PI separator. The as-prepared PI/OMMT hybrid separators showed superior electrolyte wettability and high ionic conductivity, and no thermal shrinkage occurred at 180 degrees C for 30 min. With a PI/7 wt %-OMMT hybrid separator, the cell displayed a specific discharge capacity of about 117.2 mA h g(-1) and a good capacity retention of 86.6% after 100 cycles at 0.5 C. Furthermore, the cell showed excellent rate performance and good recovery capability. Overall, the study reveals a novel solution blow-spun PI/OMMT hybrid separator as a promising candidate for high-security lithium-ion battery separators.